The iPhone 4S, the fifth iteration of Apple's iconic product, was unveiled on Oct. 4. The latest offering from Cupertino, while retaining the exterior design of its predecessor, featured important upgrades.

The most prominent features, perhaps, were Siri - a voice-recognition feature that allows users to control phones by talking to them; cloud-sourced data; and an improved 8 megapixel camera. It also has a 3.5-inch TFT Retina multi-touch display and is loaded with the latest Apple operating system - iOS 5.

On the other hand, the LG Nitro HD, which runs on Google Inc.'s Android 2.3 Gingerbread operating system, was made available on AT&T's network from Dec. 4. The LG's flagship Android phone has a powerful dual core 1.5 Ghz Qualcomm processor under its hood. It also has a 4.5-inch True HD AH-IPS display, 1GB of RAM, 4GB of internal memory plus an included 16GB microSD card, an 8 megapixel rear-facing LED flash camera with 1080p video capture and a secondary front-facing camera for video calls.

Take a look at the specifications of LG Nitro HD and Apple iPhone 4S:

Display: The LG Nitro HD has a huge screen compared to the iPhone 4S. The LG mobile comes with 4.5-inch True HD AH-IPS (Advanced High-Performance In-Plane Switching) capacitive touch screen with 1280 x 720 pixels resolution at about 326 ppi pixel density, while the iPhone 4S has 3.5-inch TFT Retina multi-touch display that may give a resolution of 960 x 640 pixels at 326 ppi density.

Dimensions: The Nitro HD comes with 133.9 x 67.8 x 10.4 mm dimension and weighs 128 grams. On the other hand, the iPhone 4S comes with 115.2 x 58.6 x 9.3 mm and weighs 140 grams.

Operating Systems: The Nitro HD runs on Android 2.3.4 Gingerbread and it is scheduled to get an Android 4.0 (Ice Cream Sandwich) update in the future. The iPhone 4S runs on iOS 5 that comes with 200 new features that include an improved Notifications System, Newsstand and iMessage.

Camera: Both smartphones sport a rear-facing 8 megapixel LED flash camera with 1080p video capture capability. For video calls, the iPhone 4S comes with a secondary VGA camera, while the Nitro HD comes with a 1.3 megapixel front-facing camera.

Processor: The Nitro HD has a very powerful processor compared to the iPhone 4S. The LG mobile is powered by a 1.5GHz Scorpion dual-core processor and Adreno 220 GPU, Qualcomm APQ8060 processor with 1GB RAM. On the other hand, the iPhone 4S, which comes in an A5 chipset, is powered by 1GHz dual-core ARM Cortex-A9 CPU, PowerVR SGX543MP2 GPU.

Connectivity: The Nitro HD has HSDPA 21 Mbps, HSUPA 5.76 Mbps and supports 4G LTE, while the iPhone 4S has HSDPA 14.4 Mbps, HSUPA 5.8 Mbps support and also has CDMA EV-DO Rev. A (800, 1900 MHz) technology.

Memory: The iPhone 4S has fixed 16/32/64 GB internal storage. On the other hand, the Nitro HD has fixed 4GB internal storage with a 16GB (expandable to 32GB) microSD card included in the package.

Battery: The iPhone 4S has a Li-Po 1420 mAh battery with 8 hours of talk time on 3G networks, up to 14 hours on 2G networks (GSM) and a standby time of 200 hours, while the Nitro HD comes with a standard Li-ion 1830 mAh battery.

Price: The Nitro HD is priced at $149.99 with a two-year AT&T contract in selected areas. On the other hand, the iPhone 4S costs $199 for the 16GB model, $299 for the 32GB model and $399 for the 64GB model.